Field of the Invention
The present invention relates to a wafer processing method.
Description of the Related Art
There has been put into practical use a manufacturing method for a semiconductor wafer having a plurality of semiconductor devices such as ICs and LSIs, wherein the semiconductor wafer is intended to improve the processing performance of the semiconductor devices. This semiconductor wafer is composed of a substrate and a functional layer formed on the front side of the substrate, wherein the functional layer is formed by stacking a plurality of low-permittivity insulator films (low-k films). Examples of each low-k film include an inorganic film of SiOF, BSG (SiOB), etc. and an organic film such as a polymer film of polyimide, parylene, etc. The semiconductor devices are formed from the functional layer of the wafer. The functional layer is brittle so that it is easily separated from the substrate in cutting the wafer by using a cutting blade. To cope with this problem, there has been performed a wafer processing method including the steps of applying a laser beam along both sides of each division line on a semiconductor wafer to form two laser processed grooves dividing the functional layer along each division line, and next positioning a cutting blade between the two laser processed grooves along each division line to relatively move the cutting blade and the semiconductor wafer, thereby cutting the wafer along each division line (see Japanese Patent Laid-open No. 2005-64231, for example).